ARCHIVES
VOL. 9, ISSUE 12 (2024)
Evaluation of mosquitocidal and antibacterial activity of tilapia gut bacterial cell-free supernatant using Culex quinquefasciatus and pathogenic bacteria
Authors
R Ramkumar, P Raja, P Balagangatharan, G S Mowniga
Abstract
Globally, mosquitoes are considered one of the
deadliest animals, responsible for millions of human fatalities each year
through the spread of infectious diseases. Initially controlled by synthetic
pesticides that protected humans, these chemicals ultimately proved harmful due
to health risks, environmental degradation, and emerging mosquito resistance.
The present study investigated the isolation and characterization of bacterial
strains from Oreochromis niloticus gut samples with potential
antibacterial and larvicidal properties. Among 69 distinct bacterial isolates
obtained, seven strains demonstrated significant larvicidal activity against Culex
quinquefasciatus 3rd larval instar, with FG16 and FG61 showing the highest
mortality rates of 70.2±3.5% and 62.2±4.6%, respectively. These two potent
isolates were identified through 16S rRNA gene sequencing as Bacillus
velezensis (NCBI accession: OP217139) and Lysinibacillus capsici
(NCBI accession: MZ227505.1), sharing 99.9% and 99.5% sequence similarity,
respectively. Both strains exhibited broad-spectrum antibacterial activity
against human and fish pathogens, with notable inhibition zones against Escherichia
coli, Klebsiella pneumonia, and Aeromonas caviae. Antibiotic
susceptibility testing revealed complete resistance to Ampicillin in both
strains, while showing varying sensitivity to other antibiotics. The cell-free
supernatant of B. velezensis demonstrated superior larvicidal efficacy
with LC50 values of 148.47, 64.22, and 42.19 mg/50mL at 12, 24, and 48 hours,
respectively, compared to L. capsici. The findings suggest that these
bacterial strains, particularly B. velezensis, hold promising potential
as biological control agents of mosquito larvae and as sources of antibacterial
compounds.
Download
Pages:95-101
How to cite this article:
R Ramkumar, P Raja, P Balagangatharan, G S Mowniga "Evaluation of mosquitocidal and antibacterial activity of tilapia gut bacterial cell-free supernatant using <i>Culex quinquefasciatus</i> and pathogenic bacteria". International Journal of Entomology Research, Vol 9, Issue 12, 2024, Pages 95-101
Download Author Certificate
Please enter the email address corresponding to this article submission to download your certificate.